There is in existence a common type of conveyor track, normally equipped with an endless driving element, which either supports or propels elements carrying materials. An example of a common type of conveyor track is a chain conveyor, where an endless chain runs over a driving and supporting wheel and either sustains elements carrying materials, such as plates or holders, or conveys materials in such a way that they are then transferred to a separate track but are sent forward by the chain. For conveyor tracks of this type the drive device must be so designed that the load-carrying elements can be attached to it in a reliable manner and use the simplest possible mechanisms, while at the same time the device must functionally work in combination with conveyance mechanisms using for example a sprocket. Such requirements often means that the driving element is constructed in the form of a chain, as in the example quoted, since the links of a chain afford good possibilities for adaptation to the attachment of goods-carriers and for a shape suitable for combination with the driving mechanism.
Technical problem:
The production of a chain involves a relatively complicated, and from the manufacturing point of view, expensive element of machinery. Even more complicated is a chain that has to bend in several planes and hence for the most part conveyor chains are made to bend in one plane only, in which case use is made of the bending property to carry a chain over the sprocket to an underlying or possibly over or lateral return coupling. This means that the conveyor track can only bend in the same direction as the plane along which the driving sections and the return section lie. In the case of a conveyor track with drive and return sections one above the other, it is possible only to raise or lower the conveyor and it cannot be shifted laterally. No torsion is possible. Of course there exist chains with dual link rings, which permit bending in several planes, but these are highly complicated and bulky.
In order to eliminate the use of complicated and expensive chains with limited bending capacity, there have been proposals to employ more continuous elements, such as lines or belts, although the latter would also have limited bending properties for sideways movement. With such elements, however, the useful property, previously referred to, of fastening the load-carrying elements and of obtaining drive coupling with the driving elements, would be lost. In general, it is necessary with such continuous elements to rely on friction joints of limited reliability instead of joined shapes. Additionally, difficulties often arise when joining or splicing sections of this type of element.
The solution:
In this invention, the driving element is shaped like a band with corrugations, between which a drive element with transverse grooves is mounted, the material in the driving element being hard and resilient and composed primarily of stiff plastic material.
Advantages:
The invention in question is for the purpose of obtaining a device for conveyor tracks in which the driving element combines advantages from both these principal types, so that the driving element can be connected to the load carrier element and the drive mechanism is completely flexible and torsionable and additionally can easily be spliced without leaving any gaps.
Another purpose of the invention is to procure a driving element which can be well adapted to production by modern manufacturing techniques and at low cost for both production itself and the associated tooling.